Merge branch 'hv/mingw-fs-funnies'

* hv/mingw-fs-funnies:
  mingw_rmdir: set errno=ENOTEMPTY when appropriate
  mingw: add fallback for rmdir in case directory is in use
  mingw: make failures to unlink or move raise a question
  mingw: work around irregular failures of unlink on windows
  mingw: move unlink wrapper to mingw.c

diff --cc compat/mingw.h
Simple merge